wilbxte



R. s. WILBUR AND R. FQLOVELEE. TELEPHONETRANSMISSION SYSTEM.

I APPLICATION map DEC, u. I917- 1,364,013. Pate ted Dec. 28, 1920..

Q [Inh- Wye/flora: Bay 5. W/Mur. fiay E10 ve/ee.

. wM/fy UNITED STATES PATENT OFFICE.

RAY s. WILBUR, OE LYNDHURsnnND RAY E. OVELEE, OE EAST ORANGE, NEW

JERSEY, ASSIGNORS To WEsTERN EL OT IO COMPANY, INOOREORATER; OF NEW YORK, N. Y., A CORPORATION OF NEW YORK. I V

TELEPHONE TRANSMISSION; SYSTEM.

- Specification of Letters Patent. Patented D GCQZS, 1920;

Application filed December 11, 1917. Serial No. 206,642. I I

This invention relates to telephone re-.

peater circuits, and more particularly to two-way, two-repeater circuits with which is associated means for amplifying ringing current or other signaling current, as well as telephonic. currents.

An object of this invention is to provide a system of this character in which the length of line over which signaling devices may be satisfactorily operated is increased.

In accordance with the features of this invention, a telephone repeater circuit having an incoming and an outgoing line section connected at a repeater station through a repeater of. the well known vacuum tube type for amplifying both telephonic and ringin currents, and in which the, input side 0 the repeater is connected with the incoming line section through a potentiometer and possibly a frequency filter for Ohtaining the greatest possible gain in ampli fication of the telephonic currents, is provided with means, preferably in the form of an electromagnetic switching device, responsive to amplified ringing current from the incomin' line section to connect the input side 0 the repeater to that line section independently of the potentiometer and filter.

This invention will be best understood from the following description when considered in connection with the accompany-.

ing drawing in which is shown a two-way, two-repeater telephone circuit COIll'filIllIlg one embodiment of this invention.

Referring to the drawing,there are shown two sections 11 and 12 of a telephone line, which are joined through repeater apparatus at a two-way, two-repeater station. The repeater arrangement comprises two vacuum tube repeaters 13 and 14 and their associated apparatus, repeater 16 being adapted to receive signalstransmitted to the station over line section 11 and: totrans mit amplified copies of these signals from the station over the line section12. In a similar manner repeater 1 1 amplifies signals I received over line section 12 and transmits such amplified signals over line section 11.

The input circuit for repeater 13 comprises impedance coils 15, 15 and condensers 16, 16

which cooperate and serve as a frequency filter for filtering out frequencies above the talking range, a potentiometer 17, normal contacts of relay 18, and the primary winding of repeating coil 19. The secondary winding of this repeating coil 19 isin circuit with battery and the filamentandthe grid of the repeater 13. The filament and the plate ofthe repeater 13 are connected'in circuit with the primary winding of an output 7- repeating coil '20, the secondary windings of which are connected in the line section 12. A relay 21, having ,two electromagnets in series with a condenser, 22 con nected in bridge of another condenser 23, is in series with the primary winding of the output repeating coil 20. Condenser23 is of such capacity that when connected in cirsuit with the primary windingof the output coil 20 the circuit is resonant to currents of talking frequencies and thecondenser'22 v is of such capacity that when ,connectedin circuitwith the windings of'the relay21 ing frequency. It will be understood therefore that relay21 will not be affected by telephonic currents. An artificial balancing line 24 is connected in circuit ,with the secondary winding of'the output repeating coil input repeating coil 29, the secondary of which is connected in circuit with battery and the filament and the grid of a repeater 14. The filament and the plate of the repeater 14: are in circuit with the "primary winding of the output repeating coil 30, the

secondary windings of which are connected in the line section 11. Relay31 and 'condensers 32 and 33 are associated with the output repeating coil 30 in precisely the same manneras relay 21"and the condensers 85 this circuit is resonant to currents of ringi 22 and 23 are associated with the output repeating coil 20, and function in the same manner. An artificial balancing line at is also associated with the output repeating coil 30.

It will be assumed that ringing current or other current having characteristics different from those of telephonic currents is transmitted to the repeater station over the line section 11. This ringing current passes from the line section 11 through the secondary windings of the output repeating coil 30, the impedance coils 15, 15, potentiometer 17, normal contacts of the relay 18 and the primary winding of the input repeating coil 19. Current is thereupon induced in the secondary circuit which includes the filament and grid of the repeater 13 and is thereby amplified and repeated into the circuit including the winding of relay 21. Relay 21 is thereupon operated to open its contact, releasing relay 40. Relay 18 is thereby operated over a circuit from battery through the windings of relay 18 and the contact of relay 10 to ground. Relay 18 in operating closes its alternate contacts, the upper and middle of which connect the primary winding of the repeating coil 19 direct to the line section 11,and the lower of which establishes a short circuit for the primary winding of the output repeating coil 30. The operation of relay 18 also opens its normal contacts, removing the potentiometer and the frequency filter from circuit relation with the primary winding of the input repeating coil 19. WVhen ringing current incoming from the line section 11 first traverses the secondary windings of the output repeating coil 80, there may be suflicient current induced in the primary thereof to operate relay 31, thereby momentarily releasing relay 4:1 and operating relay 28. However, it

this condition exists, it is for but a very of relay 28.

short period, for, as soon as the amplified ringing current operates relay 21, relay elO releases to permit the operation of relay 1.8. Belay 18 then short-circuits the primary winding of the output repeating coil 30 in the manner already described. Relay 31 will therefore immediately release, permit ting relay 41 to operate and open the circuit In other words, while both relays 21 and 31 may be operated by ringing current incoming to the repeater station from either line section, only the relay receiving am lified ringing current will remain operated. Amplified ringing current traversing the windings of relay 21 also traverses the primary winding of the output repeating coil 20, and as a result amplified ringing current is induced into the secondary windings thereof, which are in circuit with the line section 12. This ringing current transmitted over line section 11, amplified at the repeating station as described, and then induced into the line section 12, may be employed to operate signaling devices of any suitable character.

From this brief description it is thought it will be clearly understood that the apparatus functions to receive ringing current incoming over line section 12, to amplify and then to transmit such amplified current into line section 11.

What is claimed is:

1. A telephone transmission system comprising two line sections, a repeater for amplifying talking and ringing currents, a potentiometer normally connecting the input side of the repeater with one line section, an output repeating coil connecting the output side of the repeater with the other line section, and means connected in circuit with the output side of the repeater and responsive to ringing current to cause the disconnection of the potentiometer from the circuit while ringing.

2. A telephone transmission system com prising two line sections, a repeater for amplifying talking and ringing currents, potentiometer normally connecting the input side of the repeater with one line section, an output repeating coil connecting the output side of the repeater with the other line section, a relay connected in circuit with the output side of the repeater and the primary winding of the output repeating coil, and responsive to ringing current over the one line section to cause the connection of the repeater thereto independently of the potentiometer.

3. A telephone transmission system comprising two line sections, a repeater for amplifying talking and ringing currents, a potentiometer normally connecting the input side of the repeater with one line section, means connecting the output side of the repeater with the other line section, and a relay in circuit with the output side of the repeater and responsive to ringing current incoming from the one line section for causing the connection of the input side of the repeater thereto independently of the potentiometer while ringing.

4. A telephone transmission system comprising two line sections, a repeater for amplifying talking and ringing currents, a potentiometer normally connecting the input side of the repeater with one line section,

means connecting the output side of the repeater with the other line section, a relay in circuit with the output side of the .repeater and responsive to ringing current incoming from the one line section, and a second relay operating upon'the response of the first relay to connect the input side of the repeater to the one line section independently of the potentiometer.

5. A telephone transmission system comprising two line sections, a repeater for amplifying talking and ringing currents, a frequency filter and a potentiometer normally connecting the input side of the repeater with one line section, an output repeating coil connecting the output side of the repeater with the other line section, a relay connected in circuit with the output side of the repeater and the primary winding of the output repeating coil and responsive to ringing current incoming from the one line section, and a second relay energized upon the response of the first relay to disconnect the potentiometer and the frequency filter from the repeater and to connect the repeater to the one line section independently of the potentiometer and frequency filter.

6. A telephone transmission system comprising two line sections, a repeater for amplifying talking and ringing currents, at potentiometer normally connecting the input side of the repeater with one line section, an output repeating coil connecting the output side of the repeater with the other line section, and means responsive to amplified ringing current to connect the input side of the repeater with the one line section independently of the potentiometer.

7. A telephone transmission system comprisin two line sections, a repeater for ampli ying talking and signaling currents having its output side connected with one line section, means controlling the amplification of the repeater normally connecting the input side thereof with the other line section, and means responsive to amplified signaling current to connect the input side of the repeater with said other line section independently of the amplification controlling means. I

8. A telephone transmission system comprisin two line sections, a repeater for amplii ying talking and signaling currents having its output side connected with one line section, current regulating means nor mally connecting the input side of the repeater with the other line section, and means responsive to amplified signaling current to connect the inputsi'de of the repeater with said other line section independently of the current regulating means. 4

9. In a transmission system comprising two line sections, a repeater for amplifying talking and signaling currents having its input circuit connected with one section and its output circuit connected with the other section, and means responsive to amplified signaling current for increasing the efliciency of the system to signaling current.

In witness whereof, we hereunto subscribe our7names this 6th day of December, A. D. 191

RAYS. WILBUR. RAY F. LOVELEE. 

